This invention relates to a waveform converter used with an electronic musical instrument and capable of controlling the duty factor of a rectangular wave tone signal.
With a conventional electronic musical instrument, key depression causes tone signals to be selectively taken from tone generators. In this case, the tone signals are given desired tone colors by tone-coloring filters. The tone signal generators are formed of a master oscillator and a frequency divider chain consisting of cascade-connected bistable multivibrators. Tone signals produced by the tone generators have a rectangular wave and a duty factor whose value is chosen to be 50%.
When voiced by the same type of tone-coloring filter, rectangular wave tone signals having a 50% duty factor and those having other duty factors present different tone colors. If, therefore, the duty factors of rectangular wave tone signals could be freely varied, then an electronic musical instrument would provide a more improved performance.